The present invention relates to an electrohydraulic follow-up control apparatus with electrical drive means for a measuring spindle mounted turnably and axially movable in a housing which is connected with the piston in a working cylinder. The spindle, during the axial movement thereof, cooperates with valves in conduits for feeding, respectively discharging, pressure fluid into and from chambers located at opposite sides of the piston in the working cylinder. Such follow-up amplifiers are especially suitable for moving a slide in machine tools, especially when the same are constructed as disclosed in the U.S. Pat. No. 3,797,364 of the same inventor, the disclosure of which is hereby incorporated. The measuring spindle assumes the position of the slide, which is connected with the piston of the working cylinder, forming with the cylinder a hydraulic linear motor while cooperating with the valves to form with the latter a hydraulic-mechanical position regulating circuit. A direct current servomotor serves as the drive for the spindle, or else an electrical stepping motor may be used. In this way the speed, respectively, the travel information is rotary predetermined and transformed, via the pitch of the measuring spindle, into a linear movement of a given amplitude whereas the negative feedback control circuit (for instance the desired value guide via a servomotor with an incremental distance transducer system) has a range of adjustment of about 1 to 5000, the hydraulic control circuit has a range of adjustment of about 1 to one million. In machine tools it is often also required to position the tool very exactly, for instance with a tolerance of 0.001 mm and small speeds of movement, for instance 2 mm per minute, which presupposes that the spindle pitch of the measuring spindle is held very small, for instance 2 mm. Due to the necessary exact positioning and the limited range of adjustment it is possible to obtain maximum speeds of movement of about 10 meters per minute. Usually, the aforementioned electrical values are sufficient for the position- and speed regulating circuit for positioning of very exact drives.